Institutional experience with tumor budding in invasive breast carcinoma: A histopathological study of 25 cases.

Objectives: Tumor budding, defined as single cells or small clusters (≤4 cells) at the invasive front of tumors, has emerged as a histopathological marker associated with epithelial-mesenchymal transition and poor prognosis in various cancers. While widely studied in colorectal cancer, its significance in breast carcinoma remains underexplored. This study aimed to evaluate the clinicopathological relevance of tumor budding in invasive breast carcinoma of no special type operated at our institute. Material and Methods: A retrospective observational study was conducted on 25 cases of modified radical mastectomy specimens diagnosed as invasive breast carcinoma, no special type. Tumor budding was assessed on H and E-stained sections by two pathologists. Cases were categorized into low (mean <4/10 high power field (HPF) and high (≥4/10 HPF) budding groups. Correlations with clinicopathological parameters and immunohistochemical profiles estrogen receptor (ER), progesterone receptor (PR), Human Epidermal Growth Factor Receptor 2 (HER-2), Ki-67 were evaluated using the chi-square test. Results: High tumor budding was observed in 68% of cases and was significantly associated with lymphovascular invasion (p = 0.008), tumor necrosis (p = 0.001), advanced nodal stage (p = 0.029), and high Ki-67 index (p = 0.024). No significant correlation was found with age, tumor size, grade, hormone receptor status, or HER2 expression. High tumor budding was prevalent in ER-positive, HER2-negative, and Ki-67-high subtypes. Conclusion: Tumor budding correlated with several adverse histopathological features in this exploratory study. These findings suggest that tumor budding may serve as a potential prognostic histopathological marker in invasive carcinoma, particularly in setups with limited access to molecular testing. However, larger prospective studies are warranted before considering routine incorporation into histopathological reporting.